I'm knitting a scarf and the instructions read: p8, *sl next st and yo from previous row purlwise, wrap yarn counterclockwise once (this adds a new yo on top of previous), p9. What I don't understand is from the *. I've tried several ways but it's like something is missing. If I sl the next stitch and the yo from the previous row, then wrap the yard, what happens with the next stitch and the yo?

Basically, you will do a few yarn overs each row after the straight knit/purl rows by the smaller color (A) (the color that oulines the hexigons). So the first extra stitch is the smaller color (A) and then each row you will add a yarn over of the main color (B). So you slip the smaller color stitch (A) along with all the main color (B) yarn overs that you add each row.

So in Row 6, you slip two stitches. Then Row 7 it'll be three (the one stitch of Color A + 2 yarn overs from Color B).

I think I may have made this more confusing, but after the first two rows of each pattern repeat, you can see which stitches get slipped because when you get to the next full knit row with the small color (A), you knit together all the slipped stitches.